#include<iostream>
using namespace std;
#include<algorithm>


void fun()
{
    int i=0;
    int sum=0;
    for ( i = 0; i < 100; i++)
    {
        sum+=i;
    }
    cout<<sum<<endl;
}

int main()
{
    cout<<"hello world!\n"<<endl;
    fun();
    return 0;
}